A General Pathway for the Synthesis of Gallastibenes containing Ga=Sb Double Bonds

Abstract

Reactions of three equivalents of LGa {L=HC[C(Me)N(2,6-iPr C H )] } with SbX (X=F, Cl, Br, I) proceed with insertion into the Sb-X bond, elimination of LGaX , and formation of LGaSbGa(X)L (X=F 1, Cl 2, Br 3, I 4) containing a Ga=Sb double bond. In contrast, the 2:1 molar ratio reaction of LGa and SbCl initially gives the twofold insertion product [L(Cl)Ga] SbCl 7, which could not be isolated due to its strong tendency toward elimination of LGaCl and formation of distibene [L(Cl)GaSb] 5 at 25 °C or cyclotristibine [L(Cl)GaSb] 6 at 8 °C. The formation of 1-6 can be rationalized by formation of the Ga-substituted stibinidene L(X)GaSb as reaction intermediate.

Syntheses, Structures, and Bonding Analyses of Carbene‐Stabilized Stibinidenes

“…In addition, the reaction of isolated samples of 1 and 2 with one equivalent of LGa yielded previously reported gallastibenes LGaSbGa(X)L (X = Cl, Br) (Fig. S9) , …”

“…The Ga–Sb bond lengths are within the typical Ga–Sb single bond range reported for [L(X)Ga] 2 Sb 2 , [L(X)Ga] 2 Sb 4 , and L(X)GaSbGaL (X = halogen) . The largest difference in the conformations of 2 and [LGa(Br)] 2 PBr is the Br–Ga ··· Ga–Br torsion angle.…”

From π‐Bonded Gallapnictenes to Nucleophilic, Redox‐Active Metal‐Coordinated Pnictanides

“…In situ generated gallapnictenes LGaEGa(Cl)L (E=As, Sb) [8b,c] react with imidazolium chloride [IPrH][Cl] to Ga‐coordinated pnictanide anions {[LGa(Cl)] 2 E − }{IPrH + } in good yields (E=As 77 % 1 , Sb 72 % 2 , Scheme 2 c), proving the Lewis acidic character of the Ga atoms. Remarkably, the starting gallapnictenes were regenerated upon reactions of pnictanides 1 and 2 with trimethylsilyl triflate (Scheme 2 d; Figure S27, S28).…”

Von π‐gebundenen Gallapnictenen zu nukleophilen, redoxaktiven metallkoordinierten Pnictid‐Anionen

“…In situ hergestellte Gallapnictene LGaEGa(Cl)L (E=As, Sb) [8b,c] reagieren mit Imidazoliumchlorid [IPrH][Cl] in guten Ausbeuten zu Ga‐koordinierten Pnictid‐Anionen {[LGa(Cl)] 2 E − }{IPrH + } (E=As 77 % 1 , Sb 72 % 2 , Schema 2 c), was den Lewis‐aciden Charakter des Galliumatoms zeigt. Die Pnictid‐Anionen 1 und 2 können mit Trimethylsilyltriflat zudem wieder in die Gallapnictene überführt werden (Schema 2 d; Abbildung S27, S28).…”